/*
 *                               POK header
 *
 * The following file is a part of the POK project. Any modification should
 * be made according to the POK licence. You CANNOT use this file or a part
 * of a file for your own project.
 *
 * For more information on the POK licence, please see our LICENCE FILE
 *
 * Please follow the coding guidelines described in doc/CODING_GUIDELINES
 *
 *                                      Copyright (c) 2007-2021 POK team
 */

/* e_hypotf.c -- float version of e_hypot.c.
 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
 */

/*
 * ====================================================
 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
 *
 * Developed at SunPro, a Sun Microsystems, Inc. business.
 * Permission to use, copy, modify, and distribute this
 * software is freely granted, provided that this notice
 * is preserved.
 * ====================================================
 */

#ifdef POK_NEEDS_LIBMATH

#include "math_private.h"

float __ieee754_hypotf(float x, float y) {
  float a = x, b = y, t1, t2, yy1, y2, w;
  int32_t j, k, ha, hb;

  GET_FLOAT_WORD(ha, x);
  ha &= 0x7fffffff;
  GET_FLOAT_WORD(hb, y);
  hb &= 0x7fffffff;
  if (hb > ha) {
    a = y;
    b = x;
    j = ha;
    ha = hb;
    hb = j;
  } else {
    a = x;
    b = y;
  }
  SET_FLOAT_WORD(a, ha); /* a <- |a| */
  SET_FLOAT_WORD(b, hb); /* b <- |b| */
  if ((ha - hb) > 0xf000000) {
    return a + b;
  } /* x/y > 2**30 */
  k = 0;
  if (ha > 0x58800000) {    /* a>2**50 */
    if (ha >= 0x7f800000) { /* Inf or NaN */
      w = a + b;            /* for sNaN */
      if (ha == 0x7f800000)
        w = a;
      if (hb == 0x7f800000)
        w = b;
      return w;
    }
    /* scale a and b by 2**-60 */
    ha -= 0x5d800000;
    hb -= 0x5d800000;
    k += 60;
    SET_FLOAT_WORD(a, ha);
    SET_FLOAT_WORD(b, hb);
  }
  if (hb < 0x26800000) {    /* b < 2**-50 */
    if (hb <= 0x007fffff) { /* subnormal b or 0 */
      if (hb == 0)
        return a;
      SET_FLOAT_WORD(t1, 0x3f000000); /* t1=2^126 */
      b *= t1;
      a *= t1;
      k -= 126;
    } else {            /* scale a and b by 2^60 */
      ha += 0x5d800000; /* a *= 2^60 */
      hb += 0x5d800000; /* b *= 2^60 */
      k -= 60;
      SET_FLOAT_WORD(a, ha);
      SET_FLOAT_WORD(b, hb);
    }
  }
  /* medium size a and b */
  w = a - b;
  if (w > b) {
    SET_FLOAT_WORD(t1, ha & 0xfffff000);
    t2 = a - t1;
    w = __ieee754_sqrtf(t1 * t1 - (b * (-b) - t2 * (a + t1)));
  } else {
    a = a + a;
    SET_FLOAT_WORD(yy1, hb & 0xfffff000);
    y2 = b - yy1;
    SET_FLOAT_WORD(t1, ha + 0x00800000);
    t2 = a - t1;
    w = __ieee754_sqrtf(t1 * yy1 - (w * (-w) - (t1 * y2 + t2 * b)));
  }
  if (k != 0) {
    SET_FLOAT_WORD(t1, 0x3f800000 + (k << 23));
    return t1 * w;
  } else
    return w;
}
#endif
